Escapement device



Filed April 25, 1945 n JJ.

3 Sheets-Sheet 1 Npv. 2l, 1950 R. P. JAccARD 2,531,273

ESCAPEMENT DEVICE Filed April 23, 1945 3 Sheets-Sheet 2 Nov. 21, 1950 R.P. .JAccARD ESCAPEMENT DEVICE 3 Sheets-Sheet 3 Filed April 23, 1945Patented Nov. 21, 1,950

UNITED STATES OFFICE ESCAPEMENT DEVCE land Application April 23, 1945,Serial No. 589,898 In Switzerland April ,27, k1534s This inventionrelates to escapement mechanisms ior time pieces or the like, and morepar- A ticularly to a novel arrangement which is substantially shocklessand noiseless in operation.

Accordingly, a primary object of the invention is to provide anescapement mechanism wherein the shock and frictional losses are reducedto a minimum, said mechanism including an escape wheel and stop andimpulse controlling pawls each having pallet means, the stop pawl beingpivoted, to the trame while the impulse pawl is pivotally carried by anoscillating impulse transu mitting lever, said stop and impulse pawlsc0- operating with the escape wheel to easily and sub stantiallynoiselessly permit the same to move without the excess energy andirictional losses heretofore common to escapement mechanisms now ingeneral use.

With the above and other objects in view, which will more readily appearas the nature of the invention is better understood, the same consistsin the novel construction, combination, and arrangement or" partshereinafter more iully described, illustrated and claimed.

Preferred and practical embodiments of the invention are shown in theaccompanying draw-- ings, in which: A

Figure i is a side elevation, partly in section illustrating one form oithe mechanism.

Figure 2 is a cross section taken on the line A-A of Figure l.

Figure 3 is a iront elevation oi a modification of the invention.

Figure fl is a top plan View, partly in section, of the constructionshown in Figure 3.

Figure 5 is a diagrammatic view showing a variation or the inventionillustrated in Figure 2.

Figure 6 is a detail perspective view of a iurn ther variation oi theinvention including a penM dulum as the regulating means.

Figure '.7 is a detail View showing a modication similar to Figure 3.

Figure 8 is a detail perspective View of another modification of theinvention utilizing a balance wheel as the regulating means.

Similar reference characters designate corresponding parts throughoutthe several iigures of the drawings.

Referring to the drawings, it may be generally pointed out that Figuresl to 8 inclusive illus trate, by way of example, and not by waf,r oflimitation, two classes of embodiment of the invention. Figures l, 2, 5,and 6 illustrate the preferred form of the invention wherein theregulating element of the time mechanism is a pendu# 12 Claims. (Cl.58-117) lum, while `Figures 3, 4, '7, `and 8 illustrate a second classwherein the regulating element is ai balance wheel subjected to theaction of a spring.

Thus, the term regulating element or regulating means as used hereinincludes a pendulum or a spring ensioned balance wheel.

Referring to embodiments oi the rst class,

'ment mechanism ci Figures 2 and 5 has been drawn to a larger scale thanin Figure i, in order 'l to more readily understand the constructionand' operation involved. A distinctivefeature of the inventionresides inf the provision oi a pair of pawls each having pallet r engaging theteeth of the escape wheell'" said pauls being conveniently designated asfa stop pawl A and an impulse 'transmitting pawl BQ t? lformer pivotallymounted to a frame part'and' the latter pivotally carried by the end ofan oscil- 'latable drive or impulse lever C which is con nected with theregulating means, whereby the impulse of the escape wheel may beperiodically and accurately delivered to said regulating means. y InFigures l and 2, the pendulum i is flexibly'4 suspendedrby a rod :l in aconventional manner indicated as from the part 3b of a frame 3.

An escape wheel i is mounted on a shaft 4a journalled in the frame parts3 and 3a and operatively *l connected to prime mover (not shown) in theusual manner by a system of gear wheels, only-A the nrst two of which, 5and t, are shown.

Cooperating with escape wheel is arstop.

pawl A having the arms i and 'la and pivoted at 2i to the fi part saidarms terminating in what may li.d conveniently termed the safety palletsa and thestop pallet ub adapted alternatively to cooperate with theteeth of the escape wheel. While both pallets have a top action sincepallet Sb stops the escape wheel when same is moving forward indirection f1 and pallet ,9m

stops the escape .vheei when the same is pushed a safety pallet becauseit avoids extensive backward movement of the escape wheel under twoconditions, first, when the amplitude of the pendulum is larger thannecessary as might happen.,y when starting the pendulum by hand, and,second, when manually setting the hands of the..

time piece in a counterclockwise direction.

Between said escape wheel 4 and said stop pawl A, there is provided animpulse transmitting pawl B having the arms I and |03. This pawl ispivotally supported at II on the end of the shank I2 of the oscillatorylever C whose upper end is carried by shaft I3 which turns in bearingson the frame parts 3FL and 3b. A spring blade I5 fastened by a clamp I4to the shaft I3 moves back and forward in synchronism with the lever Cand during the forward movement of each complete oscillation, a yoke I6carried by the blade gives an energy impulse to the pendulum I throughthe rod 2. Owing to the flexibility of the blade I5, the oscillatorymovements of the lever C and the pendulum I, although of the samefrequency, may be quite different in their amplitude. It will be notedthat both pawls A and B have a somewhat symmetrical shape resemblingthat of a ships anchor and for that reason are stated to be of theanchor type.

Referring to Figure 2, the complete cycle of operation may be describedas follows:

The escape wheel 4 urged to move forward in the direction of the arrowf1, by the prime mover (not shown), is held back momentarily by thepallet 9b of the stop pawl A. Lever C, oscillatable with shaft I3, isshown in the middle position of its back swing in the direction of thearrow f2, during which it is driven by the pendulum I, to which it isoperatively connected by clamp I4, spring blade I5 and yoke I6. Thelever C carrying the impulse pawl B moves toward the left in Figure 2and causes cam surface I'Ib on the underside of the arm IEI of the pawlB to come in contact with the top surface of cam I 8b on the arms l ofthe stop pawl A which is momentarily at rest.

When the pallet II)b of the impulse pawl B advances toward the left androcks about pivot in the direction of arrow f7 in Figure 2 and reachesthe tooth Dl of the escape wheel it pushes the same slightly backwardsowing to the momentum of the pendulum. At that instant, the pressureexerted by tooth D2 of the escape wheel on the stop pallet 9b of thestop pawl A is relieved, and said stop pawl rocks or falls by gravity ina counter-clockwise direction according to arrow f3. The left arm 'I ofthe stop pawl A is heavier than the right arm la. This same action maybe obtained by other means, such for example as light springs, shown inFigures 3 and 5. As the stop pawl A rocks in the direction of the arrowf3, the safety pallet Se locates itself between the teeth D3 and D5 andrather close to D3 with large oscillation of the pendulum. Before thelever C reaches its extreme position on the left, tooth D3 of the escapewheel abuts against the safety pallet 9n on the right arm 'Ia of thepawl A, thus preventing excessive backward movement of the escape wheelunder either of the conditions heretofore mentioned.

Lever C terminates its back swing and begins a new oscillation forward,that is in the direction of the arrow f4, driven as it is by the impulsepawl B which is also itself pushed by the tooth D1 of the escape wheel.During a fraction of this part of the cycle, the lever C transmits animpulse of mechanical energy to the pendulum I and drives it. Theoscillation of the lever C in the forward direction continues, andcontact is established between cam surface Il at the underside of thearm I IJa of the impulse pawl B and the surface of the cam I8a on thearm Ia of the stop pawl A. 'I'his causes the stop pawl to rock in thedirection of arrow f5 and stop pallet 9b of the arm 'I locates itself inthe space between teeth D2 and D4 of the escape wheel and at the sametime the safety pallet 9a clears the escape wheel. Said escape wheel 4keeps moving in the direction of the arrow f1 until it is arrested bystop pallet 9b acting on tooth D4. Thus, stop pallet 9b has permittedescape of one tooth of the wheel in its direction of continuousmovement. The momentum of the pendulum carries the lever C farther tothe right and the pallet IUb of the impulse pawl B abandons tooth D1while the cam surf-ace I8a of the stop pawl A acting on the surface ofcam I la causes the impulse pawl B to rock in the direction of arrow f6.After the pendulum and lever C come to the end of their forwardoscillation, the said pendulum then drives the lever C back to theposition from which the present cycle began. The impulse cycle from theescape wheel to the pendulum is again completed, and the impulse cycleas well as the return cycle re- Ipeat themselves so long as the primemover (not shown) is exerting suflicent force on the escape wheel.

From the foregoing it will be apparent that there is a complete absenceof shocks during the entire cycle, as well as the absence of slidingmotion between the power transmitting elements during the time theyactually do transmit power thereby resulting in silent operation, greatsaving of power required from the prime mover, elimination oflubrication diiculties and making other improvements possible in theclocks, counters and the like.

In particular, each of the principal elements of the escapement device,namely, the wheel, the pawls, and their pallets having a simple duty toperform, their shape, and therefore their manufacture is simplified orfacilitated owing to enlarged tolerances. For instance, instead of therather complicated tooth shape common to most escape wheels, mechanismsaccording to the present invention may use straight flanked teeth.Further, each pawl and its pallets may be freely adjusted independentlyof one another. An adjustment performed on one pawl has little or noinfluence on the adjustment of the other. Further, the stiffness andshape of springs IBC I8d, and 22a may vary within reasonably largetolerances without impairing the performance of the escapementmechanisms as a whole.

It is also pointed out that the amplitude of oscillation of the lever Cis determined by the combined action of the pawls A and B with theescape wheel, and that for each complete oscillation of the pendulum,the shaft I3 receives an energy impulse from the escape wheel as thelever moves in the direction of arrow f4.

Figtue 5 shows a different arrangement of the stop pallet A' and theimpulse pallet B'. The operation of cams I8a and I8b in connection withthe corresponding surfaces of the arms IE and ||lof pawl B in Figure 2is replaced by the action of the lights springs I8c and iSd on theextension or head II!a of the shank I21 of the impulse transmittinglever Cl in Figure 5, said action being not necessarily continuous.

Figure 6 illustrates a different form of connection between theoscillating lever and pendulum which may be adapted to either form ofembodiment of the elements A and B shown in Figure 2, or A1 and B1 shownin Figure 5. Lever I4a pivoted on clamp I4b terminates in an offsetfinger I6a contacting pendulum Ib at the location of the clamp Ia. Coilspring I 5a allows lever |42L to perform a, relative angular movementwith respect Under certain ciroums vices, however, the noulum may bedriven so r to the right o; ure

that the osciilatinN lever could not follow without straining the pawlsLB or Jil-. ln spring ida gives the desired freedom 'activen thependulum and the oscillating transmitting lever.

As to the second class or devices, wherein the regulatingl element is abalance wheel, it he observed that while the balance wheel spring, inits major portion, most usually e shape oi a true spiral, as in thegrea' of Watches Where is citen ieierred "hair spring, it also t ireshape of a cylindrical coil as is u case in marine chroncmeters, or itmay oe a tefsion wire, rod, blade, or even a different The term hairspring as herein is intended to spring of any whatsoever having thecanas ity to produce the so-ealled restoring 'orce, which, in con iertiaof the bal'- ance wheel, determines the 'frequency of oscillation ofbalance Wheel.

at ,'2 on the arm of a Lohaned C2 which is p oted to the framework orthe mechanism as indicated at r'he arm the oscillating impulsetransmitting lever C2 car ries two rollersvvhich embrace the hair spring2'! of the balance wheel at a point rel near the fastening which anchorsthe i to the frame. The operatifn of the va ous eler ments in 5 ures 2'and l is in principle the same as previously descri ed. The E nsnaggedlever C2 performs the iunctions 'the lever C in Figure 2 l the of hespring 27 between e.. s I replaces the leaf spring i5 ci Figure l.

For each complete oscillation oi the balance Wheel 28, an energy impulseis in the forward direction. by the rollers liti, throfgh said hairspring t balance Figure 7 shows a different form. oi hair spring anchor.The end of the hair spring mote from the balance Wheel, instead of1oeing anchored 'to the framework at 2li as in igures 3 and 4 isfastened at 3l to the arm a of the oseillating lever C3 which in turn issubjected to the action of at least one spring t2 anchored to the frameFigure 8 is a partial perspecti e viev.,7 oi a device combi le a nai aspring, otherwise known as a torsion pendulum. In this form oiembodiment an oscillating lever C4 pivotalli7 carrying an impulse pawlB4 is itself pivoted at 24a on the frame and includes a arm 23a adaptedto engage with the iree end of an auxiliary spring means lilla whoseothe end is anchored at 2lb to the pendulum shaft ric. his arrangementgives a desirable freedom of motion between the balance wheel 28a andthe oscillating lever C4.

From the foregoing, it will ce apparent that i respectively on allembodiments of the invention include an im j pulse-tranemiting lever ordrive member C, C', C3, or C4, carrying therewith a pivotally mountedimpulse pavvl. This is true even in connection with the modificationshown in Fig. 5, Where the paWl is omitted ior the sake of clarity inillustrating the modiiied lorin connection between the oscillating leverand the pendulum.

From the foregoing it will he clear that the object of the'invention isnot limited to the arrangements shoafn in to 8 inclusive. In particular,the lever C or' Figure 2 could have a quite different orm ant, havevpivots. located elsewhere, or instance, on the axis ci the balancemember and hair spring 2l or its prolongation as is the ease lever C3 inFigure 7.

Furthermore, tl Jresent invention is not limcally driven a pendulum or abalance o applied time mecha b] the present i' utilising, for instance,meenar ally or elf`f=trically driven,

or an electroml.. .tically AWn, escapement Wheel.

claim:

l. An escapement mechanism for time pieces and the like, including, aframe, an escape Wheel having teeth and mounted :for rotation on saidframe, driving means ror driving said Wheel, regulatine" means for saidwheel including a oscilfataiz-le dr' e einher fixed "i liet meansImpulse palmeans for contro Alng the l terlittent moveT ment of theescajoe Wheel, stop pallet means being pivoted to the frame the wheeland said ise pallet i pivotally carried hy anVL sai-o. di c member ofthe regulating neans, and coo" erating means the stop pallet m ans andims ins reiative peet to the successive teeth pulse naliet 'n -M J- emovements wit or the e cape 'mit lor time pieces an escape Wheel havingte .on on said frame, driv means ior s lever c n'ieans for traregulating the essafety e ng the 'teeth oi `oallets for also-.

an impulse controlling pavvl the escape wheel,

pivotally carried the impulse transmitting lever hai of the pallets ofth s stop and safety se lever transl to the reguiovement oi the palletsof the engaging a tooth let means for alternatively engaging the teethof the escape wheel, an osciliable lever for conveying impulses from thewheel to the regulating means, an impulse controlling pawl pivoted tosaid oscillatable lever and having pallet means, and cooperating meanson said stop pawl and impulse controlling pawl for coordinating theirrelative movements.

4. An escapement mechanism for time pieces,

according to claim 3, wherein, the teeth on the escapement wheel havesubstantially straight and radial working flanks and the pallet means ofthe stop'pawl and impulse controlling pawl are complementary thereto.

5. An escapement mechanism for time pieces,

according to claim 3, wherein, the cooperating means on the stop pawland impulse pawl are inwardly projecting cams on the stop pawl andcorresponding cam surfaces on the impulse pawl.

6. An escapement mechanism for time pieces, according to claim 3,wherein, the cooperating means on the stop pawl and impulse pawl are anextension on the impulse pawl below its pivot and spring elementscarried by the stop pawl.

7. An escapement mechanism for time pieces or the like, according toclaim 3, wherein, the regulating means is a spring and balance wheel,and the oscillating lever is of substantially Z-shape formation andpivoted at one of its angles to the frame while one free end engagessaid spring and the other free end supports the impulse controllingpawl.

8. An escapement mechanism for time pieces and the like, including, aframe, an escape wheel having teeth, regulating means, a stop pawlrockably pivoted on the frame and having arms angularly disposed withrespect to the pivot, the ends of said arms having pallet means foralternately engaging the teeth of the escape wheel,

an impulse pawl having pallet means for also engaging the teeth of theescape wheel, said impulse pawl being located between the arms of thestop pawl, an oscillatable impulse transmitting lever having saidimpulse pawl pivoted at one end and having its opposite end connectedWith said regulating means, and cooperating means on the stop pawl andimpulse pawl for coordinating their relative movements with respect tothe escape wheel.

9. An escapement mechanism for time pieces and the like, including, aframe, an escape wheel having teeth, regulating means, a two armed stoppawl pivoted to the frame and having pallet means at the ends of thearms for alternate engagement with the teeth of the escape Wheel, a twoarmed impulse pawl having pallet means for engaging the teeth of theescape wheel, said impulse pawl being located between the arms of thestop pawl, an oscillatable impulse transmitting lever having the impulsepawl pivoted to one end and having its opposite end connected with saidregulating means, and cooperating means on the stop pawl and impulsepawl for coordinating their relative movements with respect to theescape Wheel.

10. A substantially shockless and noiseless escapement for time pieces,including, a frame, an escape wheel having teeth and supported by theframe, regulating means also supported by the frame, an oscillatableimpulse transmitting lever having one end connected to said regulatingmeans, impulse pallet means pivotally connected to the other end of saidlever, stop pallet means pivoted for rocking movement on the frame, andcooperating means on the impulse pallet means and stop pallet means forcoordinating their relative movements with respect to the teeth of theescape wheel, whereby, the turning effort of the Wheel is cushioned withrespect to the stop pallet means by the impulse transmitting elementconnected to the regulating means.

11. In a substantially shockless and noiseless escapement for timepieces and the like, a frame, an escape wheel having teeth, regulatingmeans for the wheel an oscillatable lever connected with said regulatingmeans, and a pair of anchor type pallet elements for engaging the teethof the wheel, one of said pallet elements being pivoted to the frame andthe other being pivoted to said oscillatable lever, and cooperatingmeans on the pallet elements for coordinating their relative movementswith respect to the teeth of the escapement wheel.

l2. An escapement mechanism for time pieces and the like, including, aframe, an escape wheel mounted on said frame and having teeth,regulating means for the wheel, a two-armed stop pawl pivoted to theframe adjacent the wheel and having stop and safety pallets respectivelyat the end of each arm for alternate engagement with the teeth of theescape wheel, said stop pallet limiting the forward movement of saidescape wheel and said safety pallet limiting the backward movementthereof, an oscillatable impulsetransmitting lever pivotally supportedat its up- I per end in the frame and connected to the reg- REN PHILIPPEJACCARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 244,684 Stahlberg July 19, 18811,395,148 Saul Oct. 25, 1921 FOREIGN PATENTS Number Country Date 6,409Great Britain Mar. 14, 1913 451,035 Germany Oct. 22, 1927

